1. Field
The present disclosure relates to a mercapto-based polysilsesquioxane and a method for preparing a functional polysilsesquioxane using the same.
2. Description of the Related Art
Polymer materials according to the related art have formed a big market as general-purpose materials by virtue of their advantages such as light weight, flexibility and mass producibility. However, as the need of a market for functional materials increases, it is required to conduct research and development toward designs of active functions and improvement in limited physical properties, such as thermal, mechanical and electrical properties, of conventional polymers. On the other hand, inorganic materials such as silica have excellent heat resistance and mechanical properties, but have no flexibility, show poor moldability and are not amenable to various functionalization due to the lack of organic functional groups. To solve the above-mentioned problems, many attentions have been given to development of organic/inorganic hybrid materials having a hybridized structure of organic materials and inorganic materials through a suitable structural design. In preparing an organic/inorganic hybrid material, it is important to have no problem in compatibility between an organic monomer or polymer and an inorganic monomer or polymer and to ensure stability. As one of the materials satisfying such a scientific need, highly heat resistant polysilsesquioxane that has been suggested to date through many articles and patents has been spotlighted. Particularly, a polysilsesquioxane-based material has been used widely in heat-resistant materials, weather-resistant materials, impact-resistant materials, wrapping materials, sealing materials, insulating materials, lubricants, release agents, semi-gas permeable coating agents and flexible substrates in the form of oil, rubber, resin, or the like. In addition, a polysilsesquioxane-based material has been regarded as one of the most important polymers in various industrial fields.
Meanwhile, in the case of photocurable polymer resins that have been known to date, photocuring has been carried out by adding a photoinitiator to perform photocuring by UV light irradiation as shown in the following reaction scheme.Initiator+hv→R•R•+M (monomer)→RM•
This is because it is difficult for a polymer structure to generate radicals and ions spontaneously by nature. Therefore, it is required to add a photoinitator capable of generating radicals in the presence of UV rays at a relatively low level. As a result, an additional material is needed to carry out photocuring, resulting in a complicated process. Moreover, it is not easy to carry out photocuring by irradiating UV rays under a general condition.